Reactance control system



P 6, 1966 R. SCHMIDT REACTANCE CONTROL SYSTEM 2 Sheets-Shae t 1 Filed Dec. 26, 1963 QUGQO'I'IOUII RICHARD SCHMIDT, INVENTOR.

FIG.

ATTORNEYS Sept. 6, 1966 R. SCHMIDT REACTANCE common srsmm 2 Sheets-Sheet 2 Filed Dec. 26, 1963 NGE QN Om RICHARD SCHMIDT,

INVENTOR.

BY ATTORNEYS United States Patent 3,270,985 REACTANCE CONTROL SYSTEM Richard Schmidt, Madison, Ala., assignor to the United States of America as represented by the Administrator of the National Aeronautics and Space Administration Filed Dec. 26, 1963, Ser. No. 333,770 19 Claims. (Cl. 2441) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates generally to a reactanee attitude control system for navigable bodies passing through a fluid or a non-fluid medium, and more particularly to the drive mechanism for operating such a system.

As is well known, conventional techniques for controlling the attitude of bodies such as aircraft, ships or the like passing through fluid mediums depend upon the torque reaction of the fluid medium with a movable control surface attached to and extending from the bodies into the mediums. However, in the event that the body to be controlled is moving through a substantial vacuum, such as exists in outer space, the body cannot be controlled by such forces because of the substantial absence of any fluid.

Various methods and systems have been proposed to provide attitude control for bodies such as, for example, space crafts which are traveling in a substantial vacuum, or for other reasons cannot use a movable reactance surface for control. One of the most promising systems for obtaining this control involves the use of an internal reactance force. One such system involves the use of a weighted material or reaction wheel that is displaced at a controllable rate and in a desired direction or directions within the craft in such a manner as to produce a variable torque rection against the craft thereby controlling its attitude independently of the absence or presence of a fluid medium outside of the craft. By suitably orienting the weighted material or reaction wheel within the craft, the torque can be produced about any desired craft axis and thus the movement of the craft can be varied as desired.

Although these prior known methods of controlling the attitude of a space craft have been proven feasible they have not found wide acceptance in the aerospace industry due to certain inherent disadvantages that each method possesses. Among the most noticeable disadvantages of these prior known reaction control systems is the large amount of power required to operate the systems, the heat produced within the space craft when such systems were started and stopped, the difficulty in solving the dynamical equations involved in their use, and the bearing longevity problem inherently found where a continuously rotating mass is involved. Furthermore, there has been some difficulty experienced in controlling the rate at which the space craft moves into the new attitude.

According to the present invention it has been found that these above enumerated disadvantages can be overcome by utilizing a reactance system in which the movable reaction producing mass is held motionless until movement of the craft being controlled is desired. To place the reactance system into operation, the reaction producing mass, which is preferably arranged to rotate about a movable axis, is first positioned so that the re action forces generated when it is placed in motion will produce the desired movement in the craft. A stored source of energy is then coupled to and released into the reaction producing mass thereby setting it into motion thus causing the craft to rotate about the desired axes at a predetermined rate of movement. Once the craft Patented Sept. 6, 1966 ice has attained the desired attitude its rotational motion is arrested by stopping the movement of the reaction producing mass. This is done by coupling an energy storage system to the mass which serves to extract and store all the kinetic energy contained within the mass. The stored energy is thus available for later use in restarting the motion of the reactance mass when it is again desirable to alter the attitude of the craft.

Accordingly, the primary object of this invention is to provide a control system for a craft which is extremely reliable, inexpensive to produce and operate, light in weight, produces no heating problem when it is being used and can be easily placed into operation in a minimum length of time without the aid of elaborate computing devices.

Another object of this invention is to provide a reactance control system for a craft in which the reaction producing mass is arrested when the control system is not being utilized to control the attitude of the craft.

Yet another object of this invention is to provide a reactance control system for a space craft in which the movement of the reaction producing mass is arrested by an energy storage system which stores the kinetic energy contained therein for later use in restarting the motion of the mass.

These and further objects and advantages of this invention will become more apparent upon reference to the following description, claims and appended drawings wherein:

FIGURE 1 is a perspective view, particularly in section, of a space vehicle being maneuvered during the final phases of a docking operation by a reactance control system constructed in accordance with this invention;

FIGURE 2 is a view in elevation, together with a diametrical vertical cross-section with partial cutaway, of the control system shown in FIGURE 1; and

FIGURE 3 is a cross-sectional view in slightly reduced size taken along line 33 of FIGURE 2.

In order to better understand the construction and use of this novel reaction system it will be described in connection with an earth-orbiting space vehicle. It is to be understood, however, that various other uses may be found for this novel reaction system. For example, a control system constructed in accordance with this invention will give superior results when used in an aircraft, boat, submarine or other assorted earth bound craft. Other uses will be readily apparent to those skilled in the art.

With continued reference to the accompanying drawings wherein like reference numerals designate similar parts throughout the various views, and with initial attention directed to FIGURE 1, reference numeral 10 is used to generally designate an earth-orbiting space vehicle which is entering the final phase of a docking maneuver with an earth-orbiting space station 12. The yaw, pitch and roll of the space vehicle 10 during this maneuver, as well as throughout most of its flight, is normally controlled by small attitude rockets 14 mounted on the exterior skin of the vehicle. When these rockets are operating properly the astronaut 16 is able to control the attitude of the space vehicle throughout its flight and to bring it into a proper mating with the air-lock 18 on the space station 12. Although these rockets 14 are highly reliable, it has nevertheless been found desirable to incorporate a so-called back-up" control system into the design of the space vehicle 10. Since such a backup system must be extremely reliable, relatively light, small and easily brought into operation, it was determined that a reactance control system which could be operated manually by the astronaut would be especially well suited for emergency use in outer space. Such a manually 3 operated reactance control system for use in the space vehicle is shown generally at 20.

The manually operated reactance control system consists of a reaction Wheel 22 which is coupled to and is free to rotate within a gimbal ring 26 by suitable shafts 28. A U shaped supporting housing 30 is rotatably mounted by suitable means (not shown) to the floor 32 of the space vehicle 10 and the gimbal ring 26 is rotatably suspended within this housing by suitable shafts 34. The reaction wheel 22 is thus mounted in a gimbal network. which permits three degrees of freedom, i.e., the rotational axes of the wheel 22 can be moved within the gimbals to any desired position. Once the reaction wheel 22 is properly positioned all the gimbals 2630 are locked in place so that the reaction wheel 22 is no longer free to move for reasons that will be more fully explained hereinafter.

Since the present reactance control system 20 is to normally be used Only in an emergency, such as would exist if the attitude rockets 14 of the space vehicle 10 ceased to function, it is necessary that the system be as independent as possible of all other systems within the vehicle. To realize the ultimate in simplicity and reliabil ity, it is necessary that the complete control system be manually powered and operated by the astronaut. Accordingly, the control system 20 must be provided with a manually operated drive means which is capable of both spinning the reaction wheel 22 up to the proper operating speed in a minimum of time and of sustaining such rotation over a prolonged period when such opera tion is necessary or desirable. Furthermore, the starting and stopping of the reaction wheel should, ideally, produce no heating of the space craft since such heat would have to be dissipated by the cooling system of the craft. One method by which the normally stationary reaction wheel 22 can be instantly brought up to operating speed, maintained there, and later stopped without producing such a heating problem is shown in FIGURES 2 and 3.

As seen in FIGURE 2, the drive system for the reaction wheel 22 consists of two substantially identical units 36 and 38 operationally mounted on either side of the wheel. For purposes of clarity, unit 36 will be described in detail while corresponding parts of unit 38 will be given the same numeral followed by a prime factor. Those differ ences that do occur between the construction and operation of units 36 and 38 will be more fully explained hereinafter.

The reaction wheel 22 is mounted on a shaft 40 that rides upon bearings 42 which are force-fitted within the gimbal ring 24. The drive unit 36, which is used to bring the reaction wheel 22 up to operating speed in the case of an emergency, is housed within a modified A frame 44 that is attached to the gimbal ring 24 by any suitable method such as welding or brazing. The closed end brace 46 as well as the cross-brace 48 of the A-frame 44 have apertures formed therein for receiving shafts 50 and 52, respectively. so that the Center axes of these shafts are aligned with that of the shaft 40. The shaft 50 is preferably carried by a bearing 54 that is force fitted into the aperture formed in the end 46 of the A-frame 44 while a second bearing 56 is force fitted within the aperture formed in the cross-brace 48 for carrying the end of shaft 52. Both of the shafts 50 and 52 are free to not only rotate about their center axes but also to move axial thereto.

The adjacent ends of the shafts 50 and 52 are provided with serrated or stair-step teeth 58 which mate so that the shafts are locked for rotation in a clockwise direction (as viewed from the end of unit 36) but are free to slip when either shaft is rotated in a counterclockwise direction. The adjacent ends of shafts 50' and 52 of unit 38 are also provided with serrated teeth 58 but they are cut so as to lock the shafts in a counterclockwise direction while permitting substantially independent rotation in a clockwise direction. The reasons for permitting the shafts to move laterally and to provide serrated teeth on the ends thereof will become more apparent later.

A coupling unit 60 is positioned between the adjacent ends of the shafts 40 and 52 and is adapted to selectively couple the rotational motion of one shaft to the other. For purposes of illustration the coupling unit 60 is shown as a friction clutch consisting of twoparallel clutch plates or disks 62 and 64, the plate 62 being secured to the shaft 40 while plate 64 is secured to the shaft 52. As will be apparent, when the drive shaft 52 is moved in the direction of the arrowhead 66 the clutch surfaces 68 on the plates 62 and 64 will engage thereby effectively coupling the two shafts 40 and 52 together.

Two independently operated clutch actuators are provided in the unit 36 for moving the shaft 52 in the direc tion of the arrowhead 66 and thus press clutch plate 64 into frictional engagement with plate 62. The first actuator, which is used to place the reaction wheel 22 in motion, consists of a shaft or rod 69 located within and passing through an aperture 70 formed along the center axes of shaft 50. The left hand end of the rod 69 as viewed in FIGURE 2 butts against and engages the shaft 52 While the other end of the rod is provided with a knob 72 or other suitable operating device. A turned down portion 74 is provided on the rod 69 for receiving a C ring 76 that is frictionally engaged against the inner surface of the aperture 70. This turned down portion 74 and C ring 76 permits the rod 69 to move a limited distance along its center axes without becoming separated from the aperture 70.

The second clutch actuator is used to stop the rotation of the reactance wheel and consists of a knob 78 that is mounted in a U shaped channel or groove 80 cut around the periphery of the hollow shaft 50. This arrangement permits the shaft to be moved axially while it is rotating by simply pressing in on the knob 78.

A manually operated drive system such as a coiled spring, elastic band or the like is provided in the unit 36 for instantly bringing the reaction wheel 22 up to operating speed when the knob 72 is pressed. This drive system for clarity is shown as a coiled spring 82 which has one end secured through a suitable clutch means 84, such as an electric clutch, to the shaft 52 while the other end thereof is secured to the cross-brace 48 by a peg 85. The clutch means 84 is adapted to permit the spring 82 to slip about the shaft 52 when the shaft is rotating in a clockwise direction and the spring 82 is not wound. A ratchet wheel 86 is mounted on the shaft 50 while a spring loaded pawl 88, which rides upon the wheel 86, is carried by the closed end 46 of the A-frarne. The pawl 88 will permit the ratchet wheel 86 to rotate in a clockwise direction but will not permit slippage of the wheel in the counterclockwise direction. A knob 90 is also mounted on the shaft 50 and is employed for loading the coiled spring 82 prior to its use.

in order to tell the amount of energy stored in the coil spring 82, and thereby calculate the speed with which the reaction wheel will be rotated once the energy is transferred from the spring to the wheel, an indicator can be used with the unit 36. Such an indicator is shown as calibrated marks 92 formed on the cross-brace 48. As the coil spring 82 is wound the. outer turn thereof will move along the calibrated scale thereby giving an indication of the energy contained in the spring.

A pair of springs 94 and 96 are provided for biasing the serrated teeth 58 together and the clutch plates 62 and 64 out of engagement with one another. The spring 94 is positioned between the cross-brace 48 and coiled spring 82 thereby tending to drive the shaft 52 to the right while spring 96 presses against the ratchet wheel 86 and the A-frame end 46 thus driving the shaft 50 to the left. The force exerted by each spring 94 and 96 is substantially the same so that they effectively cancel out and the shafts 5t] and 52 will, thereby, only move when an external force is applied through the knobs 72 and 78.

As mentioned hereinabove, the unit 38 is provided with a spring drive that is substantially identical to that contained in unit 36 with the exception that the serrated teeth 58' lock for rotation in a counterclockwise direction, the coil spring 82 is coiled so as to spin the reaction wheel in a clockwise direction when released, and the ratchet wheel 86' and pawl 88' will permit slippage in a counterclockwise direction. Thus it is seen that units 36 and 38 are identical except that unit 36 is designed to spin the reaction wheel 22 in a counterclockwise direction (as viewed from the end of unit 36) while unit 38 is designed to spin the wheel in a clockwise direction.

The operation of the manually operated reactancecontr-ol system can be explained in substantially the following manner. After the astronaut 16 has determined in which direction or plane the space craft is to be rotated in order to bring it into the proper attitude for rendezvousing with the orbiting space station 12, the astronaut will manually move the reaction wheel 22 within its gimbaled support until the axis or rotation plane 23 of the wheel is parallel to the desired correction plane. Since the reaction wheel is at rest, a negligible amount of reaction will be produced by moving and locking the wheel in place. The gimbal rings 24 and 26 are then locked in place by any suitable locking device such as the spring loaded serrated knob 96 (FIGURE 2) shown mounted on the shaft 28 of the gimbal ring 24. The knob is provided with a key-way 98 that engages the key 100 formed on the shaft 28 thereby preventing the shaft from rotating within the knob.

Once the gimbal rings 24 and 26 are securely locked in place the reaction wheel 22 is ready to be spun-up to operating speed by one of the spring drives. For purposes of illustration it is assumed that the space craft 10 is to be rotated in a clockwise direction about the rotational plane 23 of the reaction wheel 22. This would require that the reaction wheel 22 be rotated in a counterclockwise direction with an angular velocity sutficient to produce the desired reaction force within a given period of time. The principal equation for determining the capabilities of a given reaction wheel to produce such a reaction force is,

wherein I represents the polar moment of inertia, and w the angular velocity with subscript s indicating the space craft and r the reaction wheel. By writing w in terms of l w :I W

From Equations I and II, the moment of inertia of the reaction wheel can be found as,

If the mechanical efficiency factor of the system is expressed as n, the input energy E, for one maneuver, is,

From Equation VI it is seen that the input energy is dependent primarily on the efficiency factor of the system and secondarily on the moment of inertia.

In the present instance, the effectiveness of the reaction control system for controlling the attitude of the space craft 10 is illustrated as follows:

The reaction wheel 22 and the space craft 10 are assumed to have the following dimensions and characteristics:

Radius of the space craft (Rs) 1.5 meters.

Length of the space craft (Ls) 5 meters.

Equally distributed weights (Ws) 5000 kg.

Control angular velocity (ws) 2 (degrees/sec.) or

0.0349 (rad/see). Radius of the center line of the reaction wheel ring (Rr) 0.3 meter. Efficiency of the reaction wheel system (n) 0.97. Input energy for one maneuver (E') 15.0 m. kg.

The polar moment of inertia of the space capsule is given by,

s 5000 v m 7 u) iiFi The kinetic energy of the wheel is found using Equations III and VI,

:344 meters kg. sec.

g0 where b is the radius of the ring section of the wheel, and g is the gravitational acceleration in meters/sec. at zero altitude. The expression 3/4!) will be very small when compared to R, and can, therefore, be neglected. The weight W of the reaction wheel is,

1.: Klaus 4b The angular velocity of the wheel w is computed by Equation I as,

require the astronaut to expend the same amount of energy as would be involved in lifting 15K grams to a height of one meter. An astronaut can easily provide this energy in a few seconds by simply rotating the knob until the coil spring 82 is wound up to the desired mark on the scale 92. If desired, the coil spring can be prewound just prior to the flight of the space craft 10 thereby preventing the body heat of the astronaut from raising thus placing an added load on his life support system. Furthermore, such a prewound spring would save any time that might otherwise be lost in winding the spring later in the flight. After each operation of the spring drive system the astronaut would only have to replace that energy expended due to bearing friction or the like which is very small.

Once the coil spring 82 has the correct amount of energy stored therein, the astronaut 10 can set the reaction wheel 22 in motion by pressing the knob 72 thereby pushing shaft 52 and the clutch plate 64 into engagement with the plate 62 and out of engagement with the serrated teeth 58. This results in the coil spring being freed from the ratchet wheel 86 and coupled to the reaction wheel 22 through the clutch 60. The coil spring 82 will then unwind thereby transferring its stored energy to the reaction wheel 22 by placing the wheel in motion. This rotation of the reaction wheel 22 will in turn produce a reac tion force upon the space craft 10 thus causing the craft to rotate in the opposite direction from that in which the wheel is turning but about the same rotational axis As soon as the reaction wheel 22 is brought up to full speed, the astronaut will release the knob 72 thereby permitting the spring 94 to once again return the shaft 52 to its original position with the serrated teeth 58 in contact with one another. The coil spring 82 is now unloaded and will remain in this condition until it is used for its decelerating function as will be more fully explained hereinafter.

To stop the rotation of the reaction wheel 22 when the space Craft approaches the desired attitude the astronaut will actuate the deceleration system by pressing the knob 78' so that the shafts and 52' are moved toward the wheel thereby causing the clutch to engage. With the clutch 60' engaged the kinetic energy contained in the rotating reaction wheel 22 will be transferred to the previously unloaded coil spring 82' thus bringing the wheel to a stop. The stopping of the reaction wheel 22 in turn causes the rotation of the space craft 10 to stop and the control maneuver is completed. The ratchet wheel 86 prevents the now loaded coil spring 82' from unwinding until the knob 72' is pressed.

As will be apparent, the only energy lost during the rotation of the space craft is that expended in overcoming friction which, in the present case, is very small. This lost energy can quickly be replaced by the astronaut simply by rotating the knob 90 thereby winding the coil spring 82' up until the desired amount of stored energy is attained as indicated by the scale 92'.

To again place the reaction control system in operation it is only necessary to unlock the gimbal rings 24 and 26, position the reaction wheel 22, lock the gimbal rings and press the knob 72'. The reaction wheel 22 will then be placed in motion by the coil spring 82 and the space craft 10 will be moved into a new preselected attitude. To stop the maneuver the knob 78 is pressed and the energy of the reaction wheel stored in the coil spring 82.

In those instances where it is desirable for the reaction control system to operate over a prolonged period of time, such as where the space craft is to be slowly rotated for a number of times, the speed of the reaction wheel can be maintained at a preselected value by using a rack and pinion accelerating unit 102 consisting of a modified rack 104 and pinion 106 shown in FIGURES 2 and 3. The rack 104 consists of an arm having saw-tooth teeth 108 formed along its lower edge which are adapted to engage with similar teeth 110 formed on the pinion wheel 106. The rack 104 has an elongated slot 112 formed therein for receiving a pin or bolt 114 which permits the rack to move laterally across the pinion 106 thereby placing it in motion. The bolt 114 is preferably mounted in a slot 116 formed in the gimbal ring 24 for permitting the rack 104 to move vertically and out of engagement with the pinion wheel 106 when it is being readied for use in accelerating the reaction wheel 22.

A large geared wheel 118 is formed on the pinion wheel 106 for coupling the motion of the pinion wheel through a smaller geared wheel 120, which is mounted on the shaft 40, to the reaction wheel 22. Thus it is seen that when the rack 104 is pulled to the left in FIGURE 3 the reaction wheel 22 will be accelerated.

Since the reaction wheel can be spun in only one direction by a given rack and pinion arrangement (in a clockwise direction as seen in FIGURE 3, for example), and since it may be desirable to furnish energy to the wheel while it is rotating in the opposite direction, a second modified rack and pinion unit 122 is provided which is adapted to spin the wheel in the opposite direction. This second unit 122 can be omitted if desired since, by properly positioning the reaction wheel 22 prior to placing it in motion, any maneuver of the space craft 10 can be accomplished with the reaction wheel 22 designed for continuous rotation in only one direction.

From the foregoing it will be readily seen that the present reactance control system is extremely simple to use and, more importantly, is highly reliable. Furthermore, since the energy requirement for the reaction wheel is very small when compared to conventional systems, the astronaut can manually actuate as well as control the system. On space voyages which are to extend over a prolonged period of time the manually operated feature of the system will result in a considerable weight savings since no chemical fuels nor their storage, control or venting systems are required. The control equations for the reaction wheel system are also very simple thus eliminating the requirement that elaborate calculating systems be carried aboard the space craft. Since the reaction wheel is stationary except for those periods when a correction in the space ships attitude is being made, and then the wheel is rotating at a very low speed, the longevity bearing problems will be reduced to a minimum.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range equivalency of the claims are, therefore, to be embraced therein.

What is claimed and desired to be secured by the United States Letters Patent is:

1. In combination with a craft adapted to move through a fluid or substantial vacuum, a reactance attitude control system for controlling the angular movement of said craft around a predetermined axis thereof, comprising:

(a) bearing means mounted on said craft,

(b) reactance producing means mounted on said bearing means and adapted to be placed in rotation about an axis parallel to said predetermined axis,

(0) a source of potential energy attached to and carried by said craft for placing said reactance producing means in rotation;

((1) coupling means for selectively connecting said source of potential energy to said rcactance producing means thereby placing said reactance producing means in rotation,

said craft being moved about said predetermined axis by the reactance force produced by said reactance producing means;

(e) energy storage means mounted on said craft for receiving and storing the kinetic energy contained in said rotating reactanoe producing means; and

(f) means for connecting said rotating reactance producing means to said energy storage means so that the kinetic energy of said reactance producing means is removed therefrom and stored in said energy storage means and the movement of said craft is thereby stopped at a predetermined angular position.

2. In combination with a craft adapted to move through a fluid or substantial vacuum, a reactance attitude control system for controlling the angular movement of said craft around a predetermined axis thereof, comprising:

(a) supporting means mounted on said craft;

(b) movable reactance producing means mounted in spaced relation on said supporting means;

(c) a source of stored energy carried on said craft;

((1) coupling means for selectively coupling said source 75 of stored energy to said movable reactance producing means thereby causing said energy to be transferred from said stored source to said reactance producing means for placing said reactanoe producing means in motion,

the reactance forces produced by said moving reactance producing means acting on said craft thereby causing said craft to move at a predetermined angular velocity about said axis;

(e) mechanically operated means attached to and adapted for supplying additional energy to said reactance producing means for maintaining the motion thereof at a predetermined value; and

(f) means selectively coupled to said reactance producing means for removing the kinetic energy contained in said moving reactance producing means thus stopping the movement of said reactance producing means and said craft at a preselected angular position on said axis,

said means being adapted to store said kinetic energy for later release into said reactance producing means thereby again placing said reactance producing means in motion.

3. The combination according to claim 2 wherein said supporting means is adapted to be moved thereby changing the axis about which said craft is rotated.

4. The combination according to claim 2 wherein said source of stored energy is an elastic member which is maintained in a deformed condition until released by said coupling means.

5. The combination according to claim 2 wherein said elastic member is a spring.

6. In combination with a craft adapted to move through a fluid or substantial Vacuum, a reactance control system for controlling the angular movement of said craft around a predetermined axis thereof, comprising:

(a) movable support means mounted on said craft;

(b) rotatable shaft means mounted on said support means;

(c) reactance producing means attached to and adapted for rotating with said shaft means thereby producing an angular movement of said craft about said axis;

(d) a source of potential energy attached to and carried by said craft for placing said rotatable shaft means in motion;

(e) clutch means coupled between said rotatable shaft means and said source of potential energy,

said clutch means being adapted to selectively couple the energy of said source to said shaft means thereby placing said shaft means and said reactance producing means carried thereon in motion;

(f) manually operated loading means attached to said craft for transforming mechanical energy into potential energy and storing said potential energy in said source for later release through said clutch means;

(g) means for stopping the motion of said shaft means and said reactance producing means and thereby the rotation of said craft when said craft has reached a predetermined angular position.

7. In combination with a craft adapted to move through a fluid or substantial vacuum, a reactance control system for controlling the angular movement of said craft around a predetermined axis thereof, comprising:

(a) movable support means mounted on said craft;

(b) rotatable shaft means mounted on said support means;

(c) reactance producing means attached to and adapted for rotating with said shaft means thereby producing an angular movement of said craft about said axis;

(d) a source of potential energy attached to and carried by said craft for placing said rotatable shaft means in motion;

(e) first clutch means coupled between said rotatable shaft means and said source of potential energy,

said first clutch means being adapted to selectively couple the energy of said source to said shaft means thereby placing said shaft means and said reactance producing means carried thereon in motion;

(f) manually operated loading means attached to said shaft for transforming mechanical energy into potential energy and storing said potential energy in said source for later release through said clutch means;

(g) energy storage means attached to and adapted for receiving and storing the kinetic energy contained in said rotating reactance producing means; and

(h) second clutch means coupled between said rotatable shaft and said energy storage means,

said second clutch means being adapted to selectively couple said rotatable shaft to said energy storage means so that the kinetic energy of said reactance producing means is removed therefrom and stored in said energy storage means and the rotation of said craft is thereby stopped at a predetermined angular position.

8. The combination according to claim 7 wherein indicator means is operably connected to said source of potential energy for indicating the amount of energy stored therein.

9. The combination according to claim 7 wherein said movable support means is a gimbal assembly which permits said rotatable shaft means to be positioned in parallel with any predetermined axis of said craft.

10. The combination according to claim 9 wherein locking means are attached to said gimbal assembly for locking said assembly against movement in respect to said craft once said assembly is properly positioned along said predetermined axis.

11. The combination according to claim. 7 wherein a rack and pinion assembly is operably attached to said rotatable shaft for imparting energy to and thereby maintain the rotational speed of said shaft at a predetermined level.

12. In combination with a craft adapted to move through a fluid or substantial vacuum, a reactance control system for controlling the angular movement of said craft around a predetermined axis thereof, comprising:

(a) a gimbal assembly consisting of at least an inner and outer ring having mutually perpendicular intersecting axes of rotation with said outer ring being rotatably secured to said craft;

(b) selectively operated locking means attached to said inner and outer rings for securing said rings against movement in respect to said craft;

(c) a first and second shaft mounted to rotate about a common axis on said inner ring with the axis of rotation thereof being mutually perpendicular to the axis of rotation and said inner ring;

(d) selectively operated clutch means mounted on the adjacent ends of said first and second shafts for rotatably securing said shafts together,

said clutch means being normally disengaged thereby permitting said shafts to rotate independently of one another;

(c) a reaction wheel attached to and adapted for rotation with said second shaft thereby producing an angular movement of said craft about said axis of rotation;

(f) an elastic member attached to said first shaft,

said elastic member being adapted for being deformed by rotating said shaft thereby storing potential mechanical energy therein;

(g) means attached to said first shaft for rotating said shaft thereby storing potential potential enegry in said elastic member;

(h) catch means attached to said first shaft for locking said shaft against motion when potential mechanical energy is stored in said elastic member;

(i) and means for simultaneously releasing said catch means and engaging said clutch means so that the stored potential energy in said elastic member is transferred through said first and second shafts to said reactance wheel thereby placing said wheel in motion.

13. The combination according to claim 12 wherein said elastic member is a coiled spring.

14. The combination according to claim 13 wherein an indicator is operatively associated with said coil spring for indicating the potential mechanical energy contained in said spring thereby permitting the velocity with which said reaction wheel will be rotated When said energy is transferred thereto to be accurately determined.

15. The combination according to claim 14 wherein said catch means consists of a ratchet wheel fixedly mounted on said first shaft and held against rotation in the direction in which the potential mechanical energy is urging said shaft by a pawl,

said pawl permitting said shaft to freely rotate in the other direction.

16. The combination according to claim 15 wherein said means attached to said first shaft for rotating said shaft is a knob.

17. In combination with a craft adapted to move through a fiuid or substantial vacuum, a reactance control system for controlling the angular movement of said craft around a predetermined axis thereof, comprising:

(a) a gimbal assembly consisting of at least an inner and outer ring having mutually perpendicular intersecting axes of rotation with said outer ring being rotatably secured to said craft;

(b) selectively operated locking means attached to said inner and outer rings for securing said rings against movement in respect to said craft;

(c) first, second, third, fourth and fifth shafts mounted to rotate about a common axis on said inner ring with the axis of rotation thereof being mutually perpendicular to the axis of rotation of said inner ring;

(d) first selectively operated clutch means mounted on the adjacent ends of said second and third shafts for rotatably securing said shafts together when said clutch means is operated,

said clutch means being normally disengaged thereby permitting said shafts to rotate freely of one another;

(e) second selectively operated clutch means mounted on the adjacent ends of said third and fourth shafts for rotatably securing said shafts together when said clutch means is operated,

said clutch means being normally disengaged thereby permitting said shafts to rotate freely of one another;

(f) a reaction wheel attached to and adapted for ro tation with said third shaft thereby producing an angular movement of said craft about said axis of rotation;

(g) a first spring having one end thereof attached to said second shaft and the other end thereof attached to said inner ring,

said spring being adapted for being deformed by rotating said second shaft in a first direction thereby storing potential mechanical energy;

(h) a second spring having one end thereof attached to said fourth shaft and the other end thereof attached to said inner ring,

said spring being adapted for being deformed by rotating said fourth shaft in a second direciion thereby storing potential mechanical energy;

(i) serrated teeth means formed on the adjacent ends of said first, second, fourth and fifth shafts,

(1) said serrated teeth on the adjacent ends of said first and second shafts being formed so as to lock said first and second shafts together when said first shaft is rotated in said first direction,

(2) said serrated teeth on the adjacent ends of 12 said fourth and fifth shafts being formed so as to lock said fourth and fifth shafts together when said fifth shaft is being rotated in said second direction;

(j) first pawl means carried by said inner ring and urged into engagement with a first ratchet wheel fixedly mounted on said first shaft,

said ratchet wheel and pawl means being so designed as to prevent rotation of said first shaft in said second direction while permitting said shaft to freely rotate in said first direction for storing potential mechanical energy in said first spring;

(k) second pawl means carried by said inner ring and urged into engagement with a second ratchet wheel fixedly mounted on said fifth shaft,

said ratchet Wheel and pawl means being so designed as to prevent rotation of said fifth shaft in said first direction while permitting said shaft to freely rotate in said second direction for storing potential mechanical energy in said second spring;

(l) first operating means extending through said first shaft and into engagement with the end of said second shaft,

said first operating means being adapted to slide said second shaft inwardly along its axis of rotation thereby operating said first clutch means while disengaging said serrated teeth between said first and second shafts thus permitting said first spring to transfer its potential mechanical energy to said reaction wheel to place said wheel in motion in said second direction;

(m) second operating means extending through said fifth shaft and into engagement with the end of said fourth shaft,

said second operating means being adapted to slide said fourth shaft inwardly along its axis of rotation thereby operating said second clutch means while disengaging said serrated teeth between said fourth and fifth shafts thus permitting said second spring to transfer its potential mechanical energy to said reaction wheel to place said wheel in motion in said second direction;

(n) first actuating means rotatably mounted on the outer end of said first shaft,

said first actuating means being adapted to slide said first and second shafts inwardly along their axis of rotation thereby operating said first clutch means thus permitting the kinetic energy of said rotating reaction wheel to be transferred to and stored as potential mechanical energy in said first spring for later use in restarting the rotation of said wheel; and

(0) second actuating means rotatably mounted on the outer end of said fifth shaft,

said second actuating means being adapted to slide said fourth and fifth shafts inwardly along their axis of rotation thereby operating said second clutch means thus permitting the kinetic energy of said rotating reaction wheel to be transferred to and stored as potential mechanical energy in said second spring for later use in restarting the rotation of said reaction wheel.

18. The combination according to claim 17 wherein at least one manually operated rack and pinion wheel assembly is operatively connected to said reaction wheel for transferring energy to said wheel thereby causing the velocity of said wheel to increase, said rack and pinion wheel assembly consisting of a pinion wheel gear train connected to said third shaft and a rack operatively associated with said pinion wheel gear train and carried by said inner ring.

19. The combination according to claim 18 wherein an indicator is operatively associated with each of said 13 14 first and second springs for indicating the amount of po- 3,116,035 12/ 1963 Cutler 244-1 tential mechanical energy stored in each of said springs. FOREIGN PATENTS References Cited by the Examiner UNITED STATES PATENTS 2,734,383 2/1956 Paine 741 211,412 11/1957 Australia. 5 FERGUS S. MIDDLETON, Primary Exnml'ncr. 

1. IN COMBINATION WITH SAID A CRAFT ADAPTED TO MOVE THROUGH A FLUID OR SUBSTANTIAL VACUUM, A REACTANCE ATTITUDE CONTROL SYSTEM FOR CONTROLLING THE ANGULAR MOVEMENT OF SAID CRAFT AROUND A PREDETERMINED AXIS THEREOF, COMPRISING: (A) BEARING MEANS MOUNTED ON SAID CRAFT, (B) REACTANCE PRODUCING MEANS MOUNTED ON SAID BEARING MEANS AND ADAPTED TO BE PLACED IN ROTATION ABOUT AN AXIS PARALLEL TO SAID PREDETERMINED AXIS, (C) A SOURCE OF POTENTIAL ENERGY ATTACHED TO AND CARRIED BY SAID CRAFT FOR PLACING SAID REACTANCE PRODUCING MEANS IN ROTATION; (D) COUPLING MEANS FOR SELECTIVELY CONNECTING SAID SOURCE OF POTENTIAL ENERGY TO SAID REACTANCE PRODUCING MEANS THEREBY PLACING SAID REACTANCE PRODUCING MEANS IN ROTATION, SAID CRAFT BEING MOVED ABOUT SAID PREDETERMINED AXIS BY THE REACTANCE FORCE PRODUCED BY SAID REACTANCE PRODUCING MEANS; 